Water Pump is a mean of active generator cooling. It is introduced after Thermonuclear Cell had been researched.The exact workings of Water Pump are a bit complicated. First of all, pump must be placed at the shore. Game won`t allow placement otherwise, with slightly misleading message about lacking funds to do so.
Water Pump, when placed, will pump in a specific amount of water per tick (initially, 25 000) until it reaches the capacity (initially 150 000), ergo standalone vanilla Water Pump will fill itself within 6 ticks.
Water Pump will pass on water to any adjacent Water Pipe or Generator or another pump (Including Groundwater Pump). The amount of water it passes is limited only by the capacity of adjacent structures, but obviously can not be more then grand total of water currently held at the pump.
Any generator of class 2, 3 or 4, if supplied with water, will process additional heat into power, using up water at the ratio listed on Generator page. It is worth to mention that no generator can use more water per tick than it can hold. If it so happens that after processing all available heat there is still some unused water in the generator, it will remain there and can be ostensibly passed onwards via empty water pipe, but doing so is normally grossly inefficient, as generator capacity for water is nowhere near the capacity Water Works equipment boasts. Basic generators, unfortunately, are unable to take in water, and therefore will not benefit from cooling.
NOTE: Water transfer rates decay when outputting the multiple elements, and with distance from Water Pumps. Thus, even with sufficient Pump throughput to feed water to Generators, they may not receive water quickly enough to stay full.